Ha Ha, thats good, hang them up like fly papers.
Think the horse eats them then marmite smell pervades his skin and the flies dont like marmite!!!
(You either love it or hate it I guess)
Marmite contains garlic and yeast, this is why some people find it works, personally for the amount you would need to feed for it to be useful you might aswell just buy garlic and yeast powder.
There is no harm in feeding Marmite, whether it works to keep flies/midges or not is another matter.
Marmite is also a brilliant thing for disguising bute or ABs. You can either put it in a sandwich, (spread marmite first and then sprinkle drug over the top otherwise you send the powder all over the place trying to spread the marmite!) or make a sort of tea with it and pour it over food. Put a good few spoonfuls in a bowl and pour hot water over the top of it - just enough to make it dissolve so it's pourable (you can put it on neat but it's not easy as it's too sticky). I make a big bottle with a whole jar and pour a bit out each time I need it. You can also pour hot water into a nearly empty jar and give it a good shake to get the dregs out.
It works every time. It has a strong taste so disguises the medication and I have yet to come across a horse who doesn't like marmite The whole love it or hate it thing doesn't seen to apply to horses, they all love it! My boy's been on bute for a month and it's the only way I can get it down him. He has the odd sandwich just as a treat now and again as he loves them!
I have used it for my itchy pony and it really helped, I've now changed to Brewers Yeast as it's easier to mix in his food. He's a good doer and not being fed when I used the marmite so it was simple to give him a spoonful on half a slice of bread.
I was gonna say cos i hate garlic with a passion and wont eat anything with it in but i eat marmite, i thought i'd been fooled for all these years for a minute